1. Field of the Invention
The present invention relates to a new process for the preparation of benzyl cyanides optionally substituted in the aromatic ring and to alkylation of such cyanides at the alpha position.
2. Description of the Prior Art
A process of catalyzing heterogeneous ionic reactions in which the reactants are located in different liquid phases of different polarity is described in British Pat. No. 1,227,144. In this patent, the volume ratio calculated from the volume of the water excluding any dissolved material and from the starting volume of organic reactant (such as alkyl halide,) is disclosed in the examples as being in the range of from 0.2 to 1.4. Fairly high volume ratios are also mentioned in other examples of processes for conducting heterogeneous reactions described in the literature. For example, the volume ratios disclosed in Journal of the American Chemical Society 93 (1971), pages 195-199 and in Chemical Pharmaceutical Bulletin 10, (1962), pages 427-429 are 0.2 and 3.9, respectively.
Chemical Abstracts 64 (1966) 17475-17476 describes the catalytic alkylation of benzyl cyanide at the alpha position by mixing an organic phase containing benzyl cyanide and an alkyl chloride or bromide with a 50% w aqueous sodium hydroxide solution in the presence of benzyltriethylammonium chloride. Thus, a mixture of 25 mmol of benzyl cyanide, 9 ml of a 50% w aqueous sodium hydroxide solution. 0.25 mmol of benzyltriethylammonium chloride and 40 mmol of an alkyl chloride or bromide was shaken for 1 hour. The chlorides were far less reactive with respect to alkylation than the corresponding bromides, the conversions of the halide when isopropyl chloride and isopropyl bromide were used, being 2% and 43%, respectively. This, of course, implies that the conversion of the benzyl cyanide and the yield of 3-methyl-2-phenyl-butanenitrile had been correspondingly low. The very low conversion of 2% strongly suggests that isopropyl chloride is unsuitable for the commercial isopropylation of benzyl cyanide.